1. Field of the Invention
The present invention relates to an electric-powered pump that performs suction and discharging of a fluid by a driving force from a motor portion.
2. Description of the Related Art
In recent years, as fuel economy of automobiles, etc., has improved and exhaust emissions regulations have tightened, adoption of idling reduction systems has advanced as a technique that that can be expected to be highly effective in improving fuel economy and reducing emissions comparatively simply and conveniently. Idling reduction systems are systems that stop an engine during temporary stopping or during low-speed movement of an automobile and restart the engine when starting to move again. Electric-powered pumps have been used in idling reduction systems in order to generate pressure inside a transmission or to fill the transmission with oil during idling reduction in order to reduce departure shock immediately after the engine is restarted, for example. If there is a greater oil discharge flow rate from the electric-powered pump than the flow rate required on the transmission side, or changes in transmission volume arise rapidly, then oil discharging pressure in the electric-powered pump may increase temporarily.
Fuel supplying apparatuses are conventionally known in which fuel is discharged and supplied to an injector by disposing a pressure chamber in a cylinder block, and reciprocally sliding a piston inside the pressure chamber using a driving force from a motor. In the conventional fuel supplying apparatuses, a fuel pressure adjusting apparatus that adjusts fuel discharging pressure by releasing the pressure from a fuel discharging passage to an intake side when fuel discharging pressure becomes high is disposed on the cylinder block (see Patent Literature 1, for example).